Question

write the common defference of an A.P whose n th term is 3n+7

Answer 1

let n be 1 so 3(1)+7=10

let n be 2,so 3(2)+7=13

so a2-a1 is 3



i m nt sure if it is right than tell

Answer 2

hi mate

Given: 
an = 3n + 7…………(1)

Put n = 1 in eq 1
a1 = 3×1 +7
a1 = 3 +7
a1 = 10

Put n= 2 in eq 1
a2=  3×2+7
a2 = 6 +7
a2 = 13

Put n = 3 in eq 1
a3 = 3×3 +7
a3= 9 +7
a3 = 16

First three terms of an  AP are= 10, 13, 16

Common difference (d) = a2 - a1 or a3 - a2
d =  a2 - a1= 13 -10
d = 3

Hence,  the common difference of an AP is 3.

hope this helps you